Back to EveryPatent.com
United States Patent |
5,157,127
|
Weyer
,   et al.
|
October 20, 1992
|
Preparation of N-substituted pyrrolidones
Abstract
A process for the preparation of N-substituted pyrrolidones by the
catalytic hydrogenation of maleic anhydride, maleic acid and/or fumaric
acid in the presence of a primary amine and a solvent, at elevated
temperature and pressure, wherein a catalyst is used which contains cobalt
and at least one of the elements manganese, copper, phosphorus, molybdenum
and/or sodium.
Inventors:
|
Weyer; Hans-Juergen (20 Neckarpromenade, 6800 Mannheim 1, DE);
Fischer; Rolf (98 Bergstrasse, 6900 Heidelberg, DE);
Harder; Wolfgang (16 Bergwaldstrasse, 6940 Weinheim, DE)
|
Appl. No.:
|
709854 |
Filed:
|
June 4, 1991 |
Foreign Application Priority Data
Current U.S. Class: |
548/552; 548/554 |
Intern'l Class: |
C07D 207/26 |
Field of Search: |
548/552,554
|
References Cited
U.S. Patent Documents
3109005 | Oct., 1963 | Lidov | 260/326.
|
3198808 | Aug., 1965 | Himmele et al. | 548/554.
|
3884936 | May., 1975 | Hollstein | 260/326.
|
Foreign Patent Documents |
40-9149 | May., 1965 | JP | 548/554.
|
Primary Examiner: Springer; David B.
Attorney, Agent or Firm: Keil & Weinkauf
Claims
We claim:
1. A process for the preparation of N-substituted pyrrolidones which
comprises:
catalytically hydrogenating maleic anhydride, maleic acid and/or fumaric
acid in the presence of a primary aliphatic amine having from 1 to 10
carbons, a primary cycloaliphatic amine having from 5 to 8 carbons or a
primary aromatic or araliphatic amine, and in the presence of a solvent,
at a temperature of from 100.degree. to 350.degree. C. and under a
pressure of from 50 to 350 bar, said catalyst containing at least 40% w/w
of cobalt (calc. as Co), 3 to 10 w/w of manganese (calc. as Mn), 0.1 to
20% w/w of phosphoric acid, 0.01 to 1% of sodium (calc. as Na), 12 to 30%
w/w of copper (calc. as Cu) and 1 to 5% w/w of molybdenum (calc. as Mo).
2. A process as defined in claim 1, wherein maleic anhydride is
catalytically hydrogenated.
3. A process as defined in claim 2, wherein the molar ratio of maleic
anhydride to amine is from 1:0.5 to 1:2.
4. A process as defined in claim 2, wherein the molar ratio of maleic
anhydride to solvent is from 1:1 to 1:100.
5. A process as defined in claim 1, wherein the solvent used is water.
6. A process as claimed in claim 1, wherein the hydrogenation is carried
out at two different temperature and pressure levels, partial
hydrogenation being first carried out at a temperature of from 100.degree.
to 220.degree. C. and under a pressure of from 50 to 200 bar, after which
hydrogenation is completed at a temperature of from 220.degree. to
350.degree. C. and under a pressure of from 200 to 350 bar.
7. A process as defined in claim 1, wherein the amine used is methylamine.
Description
The present invention relates to a process for the preparation of
N-substituted pyrrolidones by the catalytic hydrogenation of maleic
anhydride, maleic acid and/or fumaric acid in the presence of a primary
amine and a solvent, at elevated temperature and pressure.
The abbreviations used below have the following meanings:
MAN: maleic anhydride
SAN: succinic anhydride
MA: maleic acid
FA: fumaric acid
SA: succinic acid
NMP: N-methyl pyrrolidone.
Numerous patent applications disclose methods of hydrogenating SAN/amine
mixtures, N-substituted maleinimides or succinimides to N-substituted
pyrrolidones in the presence of various special catalyst systems. All of
these methods suffer from the drawback that the said starting materials
must first be prepared, for example from MAN, in a separate reaction.
Consequently, such methods are uneconomical and of no industrial
significance for the preparation of N-substituted pyrrolidones.
On the other hand, there are only a few known processes which make it
possible to prepare N-substituted pyrrolidones directly from MAN, MA
and/or FA, as follows:
U.S. Pat. No. 3,109,005 describes a method of directly synthesizing
N-methyl pyrrolidone (NMP) by hydrogenation of MAN/methylamine mixtures in
contact with a Raney nickel catalyst at a temperature of 270.degree. C., a
pressure of 250 bar and in dioxane as solvent. With this method, reaction
times of 10 hours give yields of NMP in the region of 70%.
DE-A 2,200,600 describes the hydrogenation of MAN/methylamine mixtures to
NMP in contact with supported palladium catalysts. In this process, the
most favorable conditions, i.e. a temperature of 275.degree. C., a
pressure of 120 bar and the use of water as solvent, give a yield of 44%.
It is remarkable that almost identical reaction conditions used on the
reaction system MAN/ammonia/water give yields of 2-pyrrolidone of up to
78%. This implies that NMP is obtainable by this method clearly more
difficulty and in lower yields than 2-pyrrolidone.
Due to these moderate or unsatisfactory yields, the said processes cannot
compete with the conventional methods of preparing NMP, i.e. by reacting
.lambda.-butyrolactone with methylamine, and have attained no industrial
significance.
N-substituted pyrrolidones, particularly NMP, are manufactured in large
quantities for use as solvents and extracting agents. MAN is a cheap basic
chemical available in large quantities. It is thus an object of the
present invention to provide an economical process for the direct
synthesis of N-substituted pyrrolidones by catalytic hydrogenation of
MAN/amine mixtures. A particular object of the invention is to provide a
catalyst which makes it possible to prepare said pyrrolidones in good
yields and which is characterized by a long useful life.
Accordingly, we have found a process for the preparation of N-substituted
pyrrolidones by the catalytic hydrogenation of maleic anhydride, maleic
acid and/or fumaric acid in the presence of a primary amine and a solvent,
at elevated temperature and pressure, wherein a catalyst is used which
contains cobalt and at least one of the elements manganese, copper,
phosphorus, molybdenum and/or sodium.
The process of the invention basically relates to the hydrogenation of
MAN(I)/amine mixtures to N-substituted pyrrolidones (II), formally
represented by the following equation:
##STR1##
Examples of suitable primary amines R-NH.sub.2 for use in this reaction
are aliphatic amines having from 1 to 10, preferably from 1 to 4, carbon
atoms, primary cycloaliphatic amines having from 5 to 8 carbon atoms or,
alternatively, primary aromatic and araliphatic amines such as aniline or
benzylamine. The following amines are examples of reactants which can be
used with MAN: methylamine, propylamine, butylamine, hexylamine,
decylamine, cyclopentylamine and cyclohexylamine. It is particularly
preferred to carry out the reaction using methylamine.
The use of MA and/or FA as starting materials for the process of the
invention is equivalent to the use of MAN. All of these starting materials
may be introduced into the process of the invention in solid, liquid or
gaseous form. We particularly prefer to use MAN. An advantageous procedure
is to cause gaseous MAN, as normally produced industrially from the
catalytic oxidation of butane, butene or aromatics, to be absorbed in a
solvent and to pass the resulting solution without further treatment to
the hydrogenation reaction.
According to the invention, the catalytic hydrogenation of MAN/amine
mixtures is effected using a catalyst which contains cobalt and at least
one of the elements manganese, copper, phosphorus, molybdenum and/or
sodium. It is preferred to use catalysts which contain cobalt and at least
two of the elements manganese, copper, phosphorus, molybdenum and/or
sodium. Catalysts having particularly favorable properties when used in
the process of the invention are those which contain cobalt and at least
three of the elements manganese, copper, phosphorus, molybdenum and/or
sodium. Catalysts of this kind are described in DE-A 2,321,101 and in DE-A
3,904,083.
Examples of advantageous catalysts for use in the process of the invention
are those in which the active material contains at least 40% w/w of cobalt
(calc. as Co), the other active ingredients comprising up to 10% and
preferably from 3 to 7%, of manganese (calc. as Mn), up to 20% and
preferably from 0.1 to 5%, of phosphoric acid and up to 1% and preferably
from 0.01 to 0.5%, of sodium (calc. as Na), by weight. Of these catalysts,
those are particularly preferred in which the active material contains, as
said other active ingredients, up to 30% and preferably from 12 to 18%, of
copper (calc. as Cu) and up to 5% and preferably from 1 to 4%, of
molybdenum (calc. as Mo), by weight.
The catalysts to be used in the process of the present invention may be in
the form of supported catalysts or, preferably, solid catalysts, i.e.
unsupported catalysts. The type of support used is not normally critical
and conventional support materials, such as silicon dioxide, aluminum
dioxide, titanium dioxide, activated charcoal, silicates or zeolites, may
be used. If necessary, the catalysts may be made with the aid of binders
or shaping agents.
The catalysts are advantageously activated with hydrogen prior to use in
the process of the invention. The active catalyst components are generally
in the form of their oxides, following calcination, and the said treatment
with hydrogen reduces them, usually to the corresponding metals. Further
details on the manufacture of these catalysts can be found in DE-A
2,321,101 and DE-A 3,904,083.
The catalysts may be used in the process of the invention in the form of
suspended particles, but it is preferred to use them in a fixed bed
through which the components pass, either in a packed bubble column or,
preferably, in a trickle-bed reactor.
The hydrogenation of the reactants MAN and primary amine, as proposed by
the invention, is generally carried out in the presence of a solvent.
Suitable solvents are virtually all those which are inert to the
conditions of the hydrogenation, for example water, aliphatic and aromatic
hydrocarbons or ethers such as diethyl ether, diisopropyl ether,
methyl-t-butyl ether, dioxane or tetrahydrofuran, or mixtures of said
solvents. In one advantageous embodiment, the solvent used comprises
N-substituted pyrrolidones as produced in the hydrogenation of the
invention. It is particularly preferred to use water as solvent,
especially for the manufacture of NMP.
The order in which the reactants MAN, MA or FA and primary amine are added
to the reaction mixture is not generally critical.
The molar ratio of MAN, MA or FA to the solvent is usually from 1:1 to
1:100 and is preferably from 1:5 to 1:50.
The molar ratio of MAN, MA or FA to the primary amine in the process of the
invention is generally from 1:0.5 to 1:2, preferably from 1:0.8 to 1:1.5
and more preferably from 1:1 to 1:1.3.
The hydrogen is fed to the reaction in the stoichiometric amount or,
preferably, in excess. The excess quantity of hydrogen used is not
critical, as the excess, i.e. unconverted, hydrogen can be recycled to the
reaction or, if desired, burnt off.
Since the hydrogenation reaction of MAN, MA or FA with primary amines and
hydrogen to form N-substituted pyrrolidones proceeds via numerous
intermediates, e.g. maleaminde, maleimide, SAN, SA, succinimide and
succinamide, such intermediates can obviously themselves be used as
starting materials for the hydrogenating reaction of the invention. That
such a procedure is equivalent to the process of the invention is
self-evident.
The reaction is generally carried out at a temperature of from 100.degree.
to 350.degree. C., preferably from 150.degree. to 300.degree. C. and more
preferably from 180.degree. to 280.degree. C. The pressure used is
generally from 50 to 350 bar and preferably from 100 to 300 bar.
The reaction can be carried out batchwise, for example in stirred
autoclaves. However, it is preferred to operate the process continuously,
for example in tubular reactors or reactors incorporating a bundle of
tubes, in which case the heat of hydrogenation can be removed by external
or internal cooling. Another way of controlling the reaction temperature
is to recycle part of the effluent and the excess hydrogen after these
have been cooled in, say, a heat exchanger.
The hydrogenation reaction may be controlled in such a way that
predetermined pressure and temperature ranges are maintained throughout
the reaction. However, a positive effect on selectivity and catalyst
useful life may be achieved, particularly when relatively large amounts of
reactants are involved, by carrying out the reaction at different levels
of pressure and temperature, for example by effecting partial
hydrogenation in a first reactor at a temperature of from 100.degree. to
220.degree. C. and a pressure of from 50 to 200 bar and then transferring
the effluent as it is to the next reactor in order to complete
hydrogenation at, say, a temperature of from 220.degree. to 300.degree. C.
and a pressure of from 200 to 350 bar.
The hydrogenated reaction mixtures thus obtained may in some cases contain
not only the desired N-substituted pyrrolidones but also small amounts of
by-products such as N-substituted succinimides, succinyl diamides,
succinyl monoamides and N-substituted pyrrolidines. These mixtures can be
worked up by extraction or, advantageously, by distillation. The
separated, partially hydrogenated by-products may, since they are capable
of being hydrogenated to N-substituted pyrrolidones, be recycled to the
hydrogenation zone to complete their conversion.
The process of the invention enables N-substituted pyrrolidones to be
directly produced from MAN, MA and/or FA and primary amines on an
economical industrial scale. The yields obtained are more than 90%.
EXAMPLES
In the following Examples, the percentages are by weight.
EXAMPLE 1
The hydrogenation was carried out in a tubular reactor (length 200 mm,
diameter 16 mm) packed with 38 g of catalyst as a fixed bed. The reactor
was heated to the reaction temperature by oil contained in an external
heating jacket. The gaseous and liquid starting materials pass downwardly
through the reactor (trickle method). The hydrogenated effluent was cooled
to room temperature, depressurized and passed to a gas-liquid separator to
separate its gaseous and liquid components.
The catalyst used had the following composition:
63.4% of cobalt, calculated as CoO
18.1% of copper, calculated as CuO
6.8% of manganese, calculated as Mn.sub.3 O.sub.4
3.1% of molybdenum, calculated as MoO.sub.3
0.15% of sodium, calculated as Na.sub.2 O
3.3% of phosphoric acid (H.sub.3 PO.sub.4).
The catalyst was used in the form of gravel (particle size 2.5 to 4 mm),
which was activated with hydrogen before the commencement of the
hydrogenation reaction.
At a total pressure of 200 bar and a temperature of 250.degree. C., there
were passed through the reactor, per kg of catalyst per hour, 0.15 kg of
MAN, 0.07 kg of methylamine, 0.55 kg of water and 2,500 liters (STP) of
hydrogen.
Analysis of the liquid effluent after a reaction time of 9 hours gave a
yield of NMP of 91%, based on the weight of MAN used. There were also
found about 2% of succinyl N-methylamide and about 1% of succinyl
N-methylimide.
EXAMPLE 2
At a total pressure of 200 bar and a temperature of 210.degree. C., there
were passed through the reactor used in Example 1, per kg of catalyst per
hour, 0.1 kg of MAN, 0.15 kg of cyclohexylamine, 0.29 kg of dioxane, 0.29
kg of water and 2,000 liters (STP) of hydrogen. The yield of N-cyclohexyl
pyrrolidone, as determined by gas chromatography, was 51%, based on the
weight of MAN used.
Top